Electronics board mounting system

ABSTRACT

Apparatuses and associated methods for mounting PCBs and other electronics boards in portable medical equipment and/or other portable and non-portable electronic devices are disclosed herein. In some embodiments, the technology disclosed herein can provide PCB mounting systems that isolate the PCB from detrimental shock, vibration, and/or strain, while also providing electrical ground paths that greatly reduce EMI and other electrical disturbances. Some embodiments of the mounting systems described herein include both elastomeric (e.g., rubber) components and resilient metallic grounding members that, when assembled together, provide favorable shock mounting as well as robust electrical grounding without the inconvenience of using separate shock mounts, grounding straps, etc.

TECHNICAL FIELD

The present disclosure is generally related to mounting printed circuitboards and other electronics boards in electronic devices and, moreparticularly, to mounting systems that can reduce physical loads andelectromagnetic interference associated with such boards.

BACKGROUND

Electronic medical equipment, such as portable ultrasound imagingdevices, and many other electronic processing devices, such as laptopcomputers, typically include at least one printed circuit board (PCB)that carries a central processing unit (CPU), a graphics processing unit(GPU), a digital signal processor (DSP), and/or other electroniccomponents for operation of the device. For electromagneticcompatibility (EMC) of such devices, it can be important to shield thecomponents on the PCB from electromagnetic interference (EMI) and reduceradiated emissions that can degrade performance during operation.Additionally, especially for portable electronic devices, it can beimportant to mount the PCB in such a way that it can withstandinadvertent loads resulting from installation and use. Such loads caninclude, for example, shock loads that can occur if a user inadvertentlydrops the device. To meet these challenges, conventional electronicdevices are often designed and constructed so that they can withstand adrop of, for example, 3 feet, and provide EMI shielding sufficient tomeet Federal Communication Commission (FCC) class B regulations.

In some conventional electronic devices, the PCB is mounted to a metalenclosure or chassis with off-the-shelf rubber grommets and isolators inan attempt to mitigate shock loads. Additionally, such devices typicallyinclude one or more grounding straps having a first end attached to aperimeter of the PCB and an opposite end attached to the metal enclosurein an attempt to provide sufficient EMI shielding. Off-the-shelf rubbergrommets and isolators, however, often provide insufficient shockisolation. Similarly, the use of grounding straps typically providesonly limited EMI shielding. Moreover, the use of grounding straps canmake it difficult to mount the PCB in the enclosure, especially ifmultiple ground straps are installed around the perimeter of the PCB.Accordingly, it would be advantageous to provide PCB mounting systemsthat can provide robust protection from shock, vibration, strain and/orEMI, while also being relatively easy to install.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of a portable electronic device having anelectronics board mounting system configured in with accordance withembodiments of the present technology, and FIG. 1B is a partiallyexploded isometric view of the electronic device illustrating aspects ofthe electronics board mounting system in more detail.

FIG. 2A is an exploded isometric view of an electronics board mountingassembly configured in accordance with embodiments of the presenttechnology, FIG. 2B is an enlarged isometric view of a first supportmember of the mounting assembly of FIG. 2A, and FIG. 2C is an enlargedisometric view of a second support member of the mounting assembly ofFIG. 2A.

FIG. 3A is a cross-sectional isometric view of the mounting assembly ofFIG. 2A, and FIGS. 3B-3D are a series of isometric views illustratingvarious stages of mounting a circuit board to an enclosure with themounting assembly of FIG. 2A, in accordance with embodiments of thepresent technology.

FIG. 4A is a graph illustrating vibrational damping test results of theelectronics board mounting system of FIGS. 1A and 1B in accordance withembodiments of the present technology, and FIG. 4B is a graphillustrating electrical shielding test results of the electronics boardmounting system in accordance with embodiments of the presenttechnology.

DETAILED DESCRIPTION

The following disclosure describes various embodiments of apparatuses,systems and methods for mounting PCBs and other circuit boards inelectronic devices. As described in greater detail below, in someembodiments the apparatuses, methods and systems described herein can beused to mount PCBs in portable medical equipment and other electronicdevices in such a way that the PCB and its components are protectedagainst performance-degrading EMI, radiated emissions, and inadvertentshock, vibration, and/or strain loads.

Certain details are set forth in the following description and in FIGS.1A-4B to provide a thorough understanding of various embodiments of thepresent technology. In other instances, well-known structures,materials, operations and/or systems often associated with printedcircuit boards, electronic device enclosures, ultrasound imaging systemsand other medical equipment, etc. are not shown or described in detailin the following disclosure to avoid unnecessarily obscuring thedescription of the various embodiments of the technology. Those ofordinary skill in the art will recognize, however, that the presenttechnology can be practiced without one or more of the details set forthherein, or with other structures, methods, components, and so forth. Theterminology used below is to be interpreted in its broadest reasonablemanner, even though it is being used in conjunction with a detaileddescription of certain examples of embodiments of the technology.Indeed, certain terms may even be emphasized below; however, anyterminology intended to be interpreted in any restricted manner will beovertly and specifically defined as such in this Detailed Descriptionsection.

The accompanying Figures depict embodiments of the present technologyand are not intended to be limiting of its scope. The sizes of variousdepicted elements are not necessarily drawn to scale, and these variouselements may be arbitrarily enlarged to improve legibility. Componentdetails may be abstracted in the Figures to exclude details such asposition of components and certain precise connections between suchcomponents when such details are unnecessary for a completeunderstanding of how to make and use the invention.

Many of the details, dimensions, angles and other features shown in theFigures are merely illustrative of particular embodiments of thedisclosure. Accordingly, other embodiments can have other details,dimensions, angles and features without departing from the spirit orscope of the present invention. In addition, those of ordinary skill inthe art will appreciate that further embodiments of the invention can bepracticed without several of the details described below. In theFigures, identical reference numbers identify identical, or at leastgenerally similar, elements. To facilitate the discussion of anyparticular element, the most significant digit or digits of anyreference number refers to the Figure in which that element is firstintroduced. For example, element 110 is first introduced and discussedwith reference to FIG. 1A.

FIG. 1A is an isometric view of an electronic device 100 having anelectronics board mounting system 101 configured in accordance withembodiments of the present technology. FIG. 1B is a partially explodedisometric view of the electronic device 100 illustrating aspects of theelectronics board mounting system 101 in more detail. Referring first toFIG. 1A, in some embodiments the electronic device 100 can be a portableelectronic device, such as a portable medical device (e.g., a portableultrasound imaging device). It should be noted, however, that theelectronics board mounting system 101 described herein is not limited touse with portable electronic devices, portable medical devices, or anyother type of electronic device, but is usable with virtually any typeof processing or other electronic device that contains a PCB or otherelectronics board mounted therein.

In the illustrated embodiment, the electronic device 100 includes afirst or lower portion 102 that is pivotably connected to a second orupper portion 104 in a clamshell configuration by means of a hinge 106extending along a rear edge portion thereof. In some embodiments, theupper portion 104 can include a display (e.g., an LCD or LED), that candisplay graphical, textual, and/or other images (e.g., ultrasoundimages) when the upper portion 104 is rotated to the open position shownin FIG. 1A. In some embodiments, the lower portion 102 can include acontrol panel 112 containing various user-input devices (e.g., atouchpad, a keypad, buttons, knobs, etc.) for receiving various types ofuser input for controlling operation of the device 100. Additionally, asdescribed in greater detail below, the lower portion 102 can alsoinclude an electronics board 118 that is shock-mounted within anenclosure 110 (which can also be referred to as a housing or chassis110) and electrically grounded thereto by means of the electronics boardmounting system 101 (“mounting system 101”). In the illustratedembodiment, the electronics board 118 is a PCB that carries, forexample, one or more CPUs, GPUs, DSPs, memory, and/or other processingand/or electronic devices and circuitry for operation of the device 100in a conventional manner. In other embodiments, however, the electronicsboard 118 can be other types of circuit boards or similar substratesthat carry processing and/or other electronic components in electronicdevices that may be susceptible to shock, vibration, strain and/or EMIduring assembly, use, etc. Accordingly, the term “electronics board” isused herein to refer generally to PCBs and other structures thatmechanically support and/or electrically connect electronic components.

Referring next to FIG. 1B, in some embodiments the enclosure 110includes a first or lower cover 116 and a second or upper cover 114. Inthe illustrated embodiment, the lower cover 116 has the form of agenerally rectangular housing having a generally rectangular opening 117in an upper portion thereof, and the upper cover 114 has the form of agenerally flat panel having a rectangular shape configured to cover theopening 117. In other embodiments, however, the upper and lower covers114 and 116 and variations thereof can have other configurations. Forexample, in other embodiments the upper cover 114 can also be in theform of 3-dimensional housing or enclosure, like the lower cover 116. Insome embodiments, both the upper cover 114 and the lower cover 116 canbe formed (e.g., cast, machined, etc.) from conductive materials, suchas metallic materials (e.g., magnesium, aluminum, etc.) which are wellknown in the art and often used for electronic device enclosures.

Although not shown in FIG. 1B, in some embodiments the lower cover 116can include a plurality of integrally-formed conductive risers or bossesthat extend upwardly from an interior surface of the lower cover 116toward the opening 117. The electronics board 118 is mounted to thebosses within the lower cover 116 by a plurality of individual mountingassemblies 120 (identified individually as mounting assemblies 120 a-h).Once the electronics board 118 has been mounted to the lower cover 116as shown in FIG. 1B, the upper cover 114 can be positioned over theopening 117 and secured around the periphery thereof to secure theelectronics board 118 within the enclosure 110. In some embodiments, theconductive upper and lower covers 114 and 116 form a Faraday cage aroundthe electronics board 118 that completely encloses, or at leastsubstantially encloses, the electronics board 118. As is known, theFaraday cage can block, or at least substantially attenuate,electromagnetic fields from entering the enclosure 110 and causing EMIthat can degrade performance of the electronic components mounted to theelectronics board 118. As described in greater detail below, in someembodiments the mounting assemblies 120 can substantially isolate theelectronics board 118 from shock, vibration and strain, while alsoproviding electrical grounding paths to the lower cover 116 and theupper cover 114 that enhance EMI protection.

Although both the upper and lower covers 114 and 116 of the illustratedembodiment are formed from conductive metal, in other embodiments theelectronic device 100 can include an outer cover formed from plastic oranother non-conductive material, and the electronics board 118 can beenclosed, or at least partially enclosed, within an electricallyconductive internal enclosure (e.g., a metallic mesh enclosure)positioned within the outer plastic cover. In such embodiments, theinternal conductive enclosure can provide EMI protection, and themounting assembly 120 can be used as described herein to providegrounding paths from the electronics board 118 to the internalenclosure.

FIG. 2A is an exploded isometric view of one of the mounting assemblies120 of FIG. 1B configured in accordance with embodiments with thepresent technology. FIGS. 2B and 2C are enlarged bottom isometric viewsof a first support member 240 and a second support member 270 of themounting assembly 120, respectively, configured in accordance withembodiments with the present technology. Although only one of themounting assemblies 120 is shown in FIG. 2A, in the illustratedembodiment all of the mounting assemblies 120 are identical, or at leastsubstantially identical and, accordingly, the description that followsapplies to all the mounting assemblies 120 shown in FIG. 1B.

Referring first to FIG. 2A, as noted above in the discussion of FIG. 1B,each of the mounting assemblies 120 is operably mounted to acorresponding conductive boss 230 that extends upwardly from an interiorsurface of the lower cover 116 (FIG. 1B). In the illustrated embodiment,the boss 230 is integrally formed (e.g., cast) with the lower cover 116and accordingly formed from the same conductive material. In otherembodiments, the boss 230 can be formed separately from the lower cover116 and attached thereto by a suitable bracket, fastener, adhesive,weld, etc. The boss 230 includes a threaded fastener hole 238, which iscentrally located in an upper surface 239. In some embodiments, the boss230 can also include structural features for strength or stiffness, suchas one or more ribs 231 (identified in individually as ribs 231 a-d)that extend radially outward from the boss 230 at equal (e.g., 90degree) spacings.

In some embodiments, the mounting assembly 120 further includes astand-off 232 and a first support member 240. The stand-off 232 caninclude a hexagonal head portion 234 and a threaded portion 236separated by a shoulder 235. An upper surface 237 of the hexagonalportion 234 includes a threaded fastener hole 233. The stand-off 232 canbe made from a suitable conductive material, such as a conductive metal(e.g., mild steel).

In some embodiments, the first support member 240 (which can also bereferred to as a first isolator) can include an exterior shoulder 252concentrically positioned between a bushing portion 250 and a broaderbase portion 248. In some embodiments, the bushing portion 250 includesa plurality of deformable features 246 (e.g., elastically deformablefeatures; identified individually as deformable features 246 a-h) thatproject radially outward at even circumferential spacing around thebushing portion 250. In the illustrated embodiment, the deformablefeatures 246 have the form of longitudinal ridges with generally flat or“squared-off” outer edge portions. In other embodiments, however, thedeformable features 246 can have other shapes and sizes, such as ridgeshapes with rounded outer edge portions, or one or more of thedeformable features 246 can be omitted. In some embodiments, the supportmember 240 can also include a plurality of deformable features 254(e.g., elastically deformable features; identified individually asdeformable features 254 a-h) that extend upwardly at evencircumferential spacing around the shoulder 252. In the illustratedembodiment, the deformable features 254 have the form of protrudingsurface portions or raised “bumps” with an inverted “U” cross-sectionalshape. In other embodiments, the deformable features 254 can have othershapes, sizes and/or spacings, or one or more of the deformable features254 can be omitted.

Referring to FIG. 2A together with FIG. 2B, the first support member 240further includes a central through hole 242 extending from an uppersurface 255. In some embodiments, the through hole 242 includes a firstor upper through hole portion 242 a separated from a larger-diametersecond or lower through hole portion 242 b by an interior shoulder 256.As shown in FIG. 2B, the lower through hole portion 242 b includes aplurality of channels or grooves 260 (identified individually as grooves260 a-d) extending radially outward at equal circumferential spacing. Asdescribed in greater detail below, the grooves 260 a-d are configured tofit over the ribs 231 a-d of the boss 230.

Referring next to FIG. 2A together with FIG. 2C, the mounting assembly120 further includes a second support member 270 and an end plate orwasher 282. The second support member 270 (which can also be referred toas a second isolator) includes a central through hole 274 extending froma first or upper surface 272 to a second or lower surface 278. In someembodiments, the through hole 274 includes a first or upper through holeportion 274 a separated from a larger-diameter second or lower throughhole portion 274 b by an interior shoulder 276. As best seen in FIG. 2C,the second support member 270 can further include a plurality ofdeformable features 280 (e.g., elastically deformable features;identified individually as deformable features 280 a-h) projectingdownwardly at even spacing around the lower surface 278. In someembodiments, the deformable features 280 are identical, or at leastgenerally similar in size, shape and placement, to the deformablefeatures 256 on the opposing shoulder 252 of the first support member240. In other embodiments, however, the deformable features 280 can havedifferent shapes, sizes, and/or spacings, etc., and in yet otherembodiments, one or more of the deformable features 280 can be omitted.

In some embodiments, the first support member 240 and the second supportmember 270 can be formed from a resilient and/or elastic material, suchas synthetic or natural rubber and/or other elastomeric materials, thatcan elastically deform (e.g., elastically compress; or at leastpartially elastically compress) in response to external forces. Forexample, in some embodiments the first support member 240 and the secondsupport member 270 can be formed from silicone, such as silicone havinga Shore A hardness of 20-98 durometer, 30-90 durometer, or 40-80durometer. In other embodiments, the first support member 240 and thesecond support member 270 can be made from other elastomers and/or othersuitably elastic and/or resilient materials. Accordingly, it will beunderstood that embodiments of the first support member 240 and thesecond support member 270 are not limited to any particular materialunless expressly stated herein, and can generally be made from virtuallyany material that can deflect and/or elastically deform to absorb staticand/or dynamic loads from shock, vibration, stress, strain, etc.

In some embodiments, the washer 282 can include a plurality of recesses286 (identified individually as recesses 286 a-l) circumferentiallypositioned at equal spacing around a central through hole 284. In theillustrated embodiment, the recesses 286 are formed by correspondingthrough holes positioned at 30 degree intervals around the centralthrough hole 284. In other embodiments, the washer 282 can include moreof fewer of the recesses 286 at different spacings. Although therecesses 286 are formed by through holes in the illustrated embodiment(use of through holes simplifies manufacture and use of the washer 282),in other embodiments the recesses 286 can be formed by dimples, grooves,and/or other features, and in some embodiments, the recesses 286 can beomitted. In some embodiments, the washer 292 can be formed from asuitable conductive metal, such as beryllium copper, mild steel, etc.,and can have the same diameter, or at least approximately the samediameter, as the second support member 270. In other embodiments, thewasher 282 can have other shapes and sizes, and can be made from othersuitable materials.

In some embodiments, the mounting assembly 120 further includes a firstgrounding member 290 a, a second grounding member 290 b, and a fastener266. In the illustrated embodiment, the first grounding member 290 aincludes a distal portion 293 that extends at an angle from a baseportion 292. The base portion 292 includes a through hole 294 and a“bump” or rounded protrusion 296 that projects downwardly toward thewasher 282. More specifically, the protrusion 296 is located the sameradial distance from the through hole 294 as the recesses 286 arelocated from the through hole 284 in the washer 282. The distal portion293 of the first grounding member 290 a includes a tip portion having acontact surface 298 that is formed to extend outwardly generallyparallel to the base portion 292. In the illustrated embodiment, thesecond grounding member 290 b can be identical, or at least generalsimilar in structure and function to the first grounding member 290 a,with the exception that the second grounding member 290 b can be flippedover 180 degrees so that the distal contact surface 298 projectsupwardly from the corresponding base portion 292 as shown in FIG. 2A.

In some embodiments, the grounding members 290 can be formed from arelatively thin conductive metal sheet material that exhibits resilientor spring-like qualities while also being electrically conductive. Forexample, in some embodiments the grounding members 290 can be formedfrom beryllium copper sheet, such as beryllium copper sheet having athickness of from 0.0005 inch to 0.025 inch, from 0.001 inch to 0.018inch, or from 0.005 inch to 0.012 inch. In other embodiments, thegrounding members 290 (which can also be referred to as “fingers,”“conductive fingers,” “conductive contracts,” etc.) can be formed fromother suitable electrically conductive materials having suitableresiliency to return to their original shape after the contact tipsurface 298 has been deflected.

The electronics board 118 includes a through hole 262 configured toreceive the bushing portion 250 of the first support member 240.Although the through hole 262 is depicted as a complete circular hole inFIG. 2A, it should be noted that some embodiments the mounting assembly120 can be used at or near an edge of the electronics board 118, inwhich case the through hole 262 may only form a portion of a circularhole in the electronics board 118. In some embodiments, the through hole262 can have the same diameter, or at least approximately the samediameter, as the bushing portion 250. In other embodiments, the throughhole 262 can be configured to provide a clearance fit for the bushingportion 250 (e.g., a fit in which the through hole 262 is slightlylarger (e.g., 0.0005 to 0.030 inch larger) than the outer diameter ofthe bushing portion 250. In still further embodiments, the through hole262 can be configured to provide an interference fit for the bushingportion 250 (e.g., a fit in which the though hole 262 is smaller (e.g.,0.0005 to 0.010 inch smaller) than the bushing portion 250.

The electronics board 118 can further include a grounding pad 264positioned proximate to the through hole 262. In the illustratedembodiment, the grounding pad 264 provides a conductive surface thatextends through an arch of from about 10 degrees to about 140 degrees,or about 80 degrees around the through hole 262. In other embodiments,the grounding pad 264 can extend completely around the through hole 262.The grounding pad 264 can be shaped to have a first radius R₁ and asecond radius R₂ that are selected to position the contact surface 298of the first grounding member 290 a generally in the radial center ofthe grounding pad 264. In some embodiments, the grounding pad 264 can belaminated onto or into the surface of the electronics board 118 toprovide a conductive contact surface that is readily accessible by thecontact surface 298 of the first grounding member 290 a. For example, insome embodiments the grounding pad 264 can be made from a suitableconductive foil, such as a gold-over-copper foil well known in themanufacture of PCBs and other circuit boards. Additionally, thegrounding pad 264 can be electrically connected through one or moreground paths (not shown) to one or more ground planes 265 in theelectronics board 118. In some embodiments, the ground plane 265 can beformed in or on the surface of the electronics board 118 in aconventional manner, and can be comprised of copper foil or othersuitable materials well known in the art.

FIG. 3A is an isometric cross-sectional view of the assembled mountingassembly 120 at one of the mounting locations of the electronics board118 in accordance with the embodiments of the present technology. FIGS.3B-3D are a series of top isometric views illustrating various stages ofinstalling the electronics board 118 in the enclosure 110 (FIG. 1B) inaccordance with embodiments of the present technology. Referring to FIG.3A together with FIG. 2A, to assemble the mounting assembly 120 andinstall the electronics board 118 in the enclosure 110, the threadedportion 236 of the stand-off 232 is threadedly inserted into thethreaded hole 238 in the boss 230. The hexagonal portion 234 of thestand-off 232 can facilitate tightening of the stand-off 232 into theboss 230. After the stand-off 232 has been attached to the boss 230, thefirst support member 240 is positioned over the stand-off 232 so thatthe ribs 231 a-d of the boss 230 are received in the grooves 260 a-d ofthe first support member 240 (FIG. 2B), and the upper surface 239 of theboss 230 contacts the shoulder 256 of the first support member 240 (alsoFIG. 2B). When the first support member 240 is in this position, theupper surface 237 of the stand-off 232 protrudes slightly above theadjacent upper surface 255 of the bushing portion 250, as shown in, forexample, FIGS. 3A and 3C.

FIG. 3B illustrates a stage in the installation of the electronics board118 in which a plurality of the stand-offs 232 (identified individuallyas stand-offs 232 a-h) and a plurality of the first support members 240(identified individually as first support members 240 a-240 h) have beenmounted to corresponding bosses 230 in the manner described above. Next,the electronics board 118 is positioned over the first support members240 so that each of the bushing portions 250 is received in acorresponding one of the openings 262 in the electronics board 118 asshown in, for example, FIGS. 3A and 3C. Next, the second support member270 is positioned over the first support member 240 so that the bushingportion 250 of the first support member 240 contacts the interiorshoulder 276 on the second support member 270 (FIGS. 2C and 3A). At thisstage, the hexagonal portion 234 of the stand-off 232 extends at leastpartially through the upper through hole portion 274 a of the secondsupport member 270 so that the upper surface 237 of the stand-off 232 ispositioned flush with, or just slightly below, the upper surface 272 ofthe second support member 270 (FIGS. 2A, 2C and 3A).

Next, the washer 282 is centrically positioned over the second supportmember 270, followed by the first grounding member 290 a and the secondgrounding 290 b. The threaded portion 268 of the fastener 266 is theninserted through the through holes 294 and 284 and threadedly insertedinto the threaded hole 233 in the stand-off 232, as shown in FIG. 3A.Before the fastener 266 is fully tightened, however, the first groundingmember 290 a can be rotated in either direction about the fastener 266to position the contact surface 298 in direct, intimate contact with thegrounding pad 264 on the electronics board 118, as shown in, forexample, FIG. 3D. Additionally, the second grounding member 290 b canalso be rotated into a favorable position so that its contact surface298 will make direct and intimate contact with an adjacent interiorsurface of the upper cover 114 of the enclosure 110 (FIG. 1B) once theupper cover 114 has been installed on the lower cover 116. Once thefirst and second grounding members 290 have been rotated into thedesired angular positions, the fastener 266 can be fully tightened.Doing this holds the protrusion 296 on the first grounding member 290 ain the corresponding opening 286 in the washer 282, to thereby maintainthe first grounding member 290 a in the desired angular position. Afterthe electronics board 118 has been fully mounted to the lower cover 116,the upper cover 114 can be secured over the opening 117 in the lowercover 116 (FIG. 1B).

As shown in FIG. 3A, when the fastener 266 is fully tightened the washer282 is brought firmly to bear against the upper surface 237 of thestand-off 232, and the first and second support members 240 and 270,respectively, are slightly compressed between the washer 282 and theboss 230. As a result, the electronics board 118 is compressed betweenthe deformable features 254 on the first support member 240 (FIG. 2A) onthe bottom side, and the deformable features 280 on the second supportmember 270 (FIG. 2C) on the top side. However, because of their elasticcompressibility, the first support member 240 and the second supportmember 270 provide an elastic mounting arrangement for the electronicsboard 118 that can greatly attenuate shock loads on, and/or dampenvibration of, the electronics board 118 resulting from, for example, theelectronic device 100 (FIG. 1A) being inadvertently dropped by a user.Additionally, the compliant nature of the first support member 240 andthe second support member 270 also enables them to reduce strain on theelectronics board 118 (and associated stress) that can occur duringinstallation (because of, e.g., misalignment of the mounting bosses 230,manufacturing tolerances, etc.), and/or during use (because of, e.g.,thermal loads, device mishandling, etc.). By way of example only, insome embodiments the first support member 240 and the second supportmember 270 can enable upward and downward movement of the electronicsboard 118 (i.e., movement perpendicular to the electronics board 118) ofup to 0.075 inch, or up to 0.050 inch, without sustaining damage. By wayof another example, in some embodiments the deformable features 246 onthe bushing portion 250 (in combination with other features of the firstsupport member 240 and the second support member 270; FIG. 2A) canenable lateral movement of the electronics board 118 (i.e., side-to-sidemovement in the plane of the electronics board 118) of up to 0.200 inch,or up to 0.160 inch, without sustaining damage.

Another aspect of the present technology is that, in some embodiments,the compliance of the grounding members 290 can be matched, or at leastapproximately matched, to the compliance of the first and second supportmembers 240 and 270, respectively. Matching compliances in this mannercan ensure that the first grounding member 290 a maintains conductivecontact with the grounding pad 264, and the second grounding member 290b maintains conductive contact with the upper cover 114, even while theelectronics board 118 may be moving or vibrating in response to, forexample, extreme shock loads. For example, in some embodiments the firstgrounding member 290 a can be formed so that, as the fastener 266 isfully tightened, the grounding pad 264 contacts the contact surface 298and causes the distal portion 293 of the grounding member 290 a todeflect upwardly a preset amount (e.g., 0.10 inch or less, or 0.080 inchor less). This deflection “preloads” the first grounding member 290 a,and enables the contact surface 298 to maintain contact with thegrounding pad 264 in harsh vibratory environments, even if theelectronics board 118 moves away from the grounding member 290 a inresponse to, for example, an extreme shock load. Similarly, the secondgrounding member 290 b can be formed so that an interior surface portionof the upper cover 114 contacts the contact surface 298 of the secondgrounding member 290 b as the upper cover 114 is installed on the lowercover 116, causing the distal portion 293 of the second grounding member290 b to deflect downwardly a preset amount (e.g., 0.080 inch or less)when the upper cover 114 is fully installed. This preset deflectionenables the contact surface 298 of the second grounding member 290 b tomaintain contact with the upper cover 114, even in harsh vibratoryenvironments. By maintaining conductive contact between the firstgrounding member 290 a and the grounding pad 264, and between the secondgrounding member 290 b and the upper cover 114, the mounting assemblycan ensure that the Faraday cage around the electronics board 118 ismaintained and performance is not degraded, even in extreme useconditions.

There are a number of other advantages associated with the embodimentsof the present technology. For example, in some embodiments usingmultiple of the mounting assemblies 120 around not just the perimeterbut also the interior portion of the electronics board 118 (at, e.g.,spacings of about 3-4 inches) provides a multi-point shock mountingsystem that can substantially reduce potentially detrimental loads onthe electronics board 118 resulting from shock and vibration (e.g., frombeing dropped), as well as strained, (e.g., strain resulting frommanufacturing tolerances, etc.). Moreover, the multi-point mountingassemblies also provide multiple ground locations to both the top andbottom surfaces of the Faraday cage provided by the upper cover 114 andthe lower cover 116 (FIG. 1B). More specifically, in some embodimentsthe first grounding member 290 a provides a direct ground path from thecorresponding grounding pad 264 (and thus the electronics board groundplane 265) to the lower cover 116 by means of the boss 230. Moreover,the first grounding member 190 a also provides a portion of the groundpath from the grounding pad 264 to the upper cover 114 by means of thesecond grounding member 190 b, which provides direct contact to theupper cover 114 via the contact surface 298 of the second groundingmember 190 b. These ground paths are substantially shorter thanconventional EMI ground paths provided by, for example, grounding strapswhich are typically attached only around the perimeter of a circuitboard. Moreover, embodiments of the present technology can greatlysimplify the installation of the electronics board 118 by discarding thegrounding straps and associated fasteners of the prior art, and insteadprovide direct grounding to both the upper and lower surfaces of theFaraday cage by means of the first and second grounding members 290 aand 290 b, respectively, as described above.

FIG. 4A is a graph 400 a illustrating vibrational damping test resultsof the electronics board mounting system 101 (FIGS. 1A and 1B)configured in accordance with embodiments of the present technology. Avertical axis 402 of the graph 400 a measures accelerations in g's (g),and a horizontal axis 404 measures time in seconds (s). In thisparticular test, the enclosure 110 of the device 100 (FIGS. 1A and 1B)was excited at a level of 50 g's, as illustrated by a first plot line406. As a second plot line 408 shows, however, a heat sink mounted tothe electronics board 118 within the enclosure 110 only experienced avibration level of 6 g's, even though the outer enclosure 110 wasvibrating at a level of 50 g's. Accordingly, the graph 400 a illustratesthat mounting the electronics board 118 to the enclosure 110 with aplurality of the mounting assemblies 120 described above cansubstantially reduce inadvertent shock, vibration and/or other loads onthe electronics board 118 that may occur in use.

FIG. 4B is a graph 400 b illustrating radiated emissions test results ofthe electronics board mounting system 101 configured in accordance withembodiments of the present technology. A vertical axis 412 of the graph400 b measures radiated emissions in volts per meter (V/m), and ahorizontal axis 414 measures frequency of the emissions in Hertz (Hz). Afirst plot line 416 illustrates the radiated emissions limits as afunction of frequency required to meet FCC Class B regulations. A secondplot line 418 illustrates measured radiated emissions from theelectronics board 118 during operation. As can be seen from the secondplot line 418, the radiated emissions from the electronics board 118 aresubstantially below the limits required by the Class B regulations.Accordingly, use of the electronics board mounting assemblies 120described herein can provide effective means of isolating theelectronics board 118 and its components from shock, vibration, and/orstrain loads, while also providing robust electrical ground connectionsbetween the electronics board 118 and the enclosure 110 to reduceradiated emissions, EMI, and/or other performance-degrading occurrences.

References throughout the foregoing description to features, advantages,or similar language do not imply that all of the features and advantagesthat may be realized with the present technology should be or are in anysingle embodiment of the invention. Rather, language referring to thefeatures and advantages is understood to mean that a specific feature,advantage, or characteristic described in connection with an embodimentis included in at least one embodiment of the present technology. Thus,discussion of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment. Furthermore, the described features, advantages, andcharacteristics of the present technology may be combined in anysuitable manner in one or more embodiments. One skilled in the relevantart will recognize that the present technology can be practiced withoutone or more of the specific features or advantages of a particularembodiment. In other instances, additional features and advantages maybe recognized in certain embodiments that may not be present in allembodiments of the present technology.

Any patents and applications and other references noted above, includingany that may be listed in accompanying filing papers, are incorporatedherein by reference. Aspects of the invention can be modified, ifnecessary, to employ the systems, functions, and concepts of the variousreferences described above to provide yet further implementations of theinvention.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof means any connection or coupling,either direct or indirect, between two or more elements; the coupling orconnection between the elements can be physical, logical, or acombination thereof. Additionally, the words “herein,” “above,” “below,”and words of similar import, when used in this application, refer tothis application as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively. The word “or,” in reference to alist of two or more items, covers all of the following interpretationsof the word: any of the items in the list, all of the items in the list,and any combination of the items in the list.

The above Detailed Description of examples and embodiments of theinvention is not intended to be exhaustive or to limit the invention tothe precise form disclosed above. While specific examples for theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. The teachings ofthe invention provided herein can be applied to other systems, notnecessarily the system described above. The elements and acts of thevarious examples described above can be combined to provide furtherimplementations of the invention. Some alternative implementations ofthe invention may include not only additional elements to thoseimplementations noted above, but also may include fewer elements.Further any specific numbers noted herein are only examples: alternativeimplementations may employ differing values or ranges.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the various embodiments of the invention. Further,while various advantages associated with certain embodiments of theinvention have been described above in the context of those embodiments,other embodiments may also exhibit such advantages, and not allembodiments need necessarily exhibit such advantages to fall within thescope of the invention. Accordingly, the invention is not limited,except as by the appended claims.

Although certain aspects of the invention are presented below in certainclaim forms, the applicant contemplates the various aspects of theinvention in any number of claim forms. Accordingly, the applicantreserves the right to pursue additional claims after filing thisapplication to pursue such additional claim forms, in either thisapplication or in a continuing application.

I claim:
 1. An electronic device comprising: an enclosure having a first conductive cover spaced apart from a second conductive cover; an electronics board having a first side, a second side opposite to the first side, and a plurality of conductive surface portions on the first side; and a plurality of mounting assemblies operably supporting the electronics board in the enclosure between the first and second conductive covers, wherein each of the mounting assemblies includes a first elastic support member on the first side proximate to a first conductive portion of the conductive surface portions; and a second elastic support member on the second side of the electronics board opposite to the first side; and a grounding member contacting the first conductive surface portion and forming at least a portion of a ground path from the first conductive surface portion to at least one of the first or second conductive covers.
 2. The electronic device of claim 1 wherein the grounding member includes a tip portion biased against the first conductive surface portion in the absence of a fastener or adhesive connecting the tip portion to the first conductive surface portion.
 3. The electronic device of claim 1: wherein the first elastic support member includes a first through hole, wherein the grounding member includes a second through hole concentrically aligned with the first through hole, and wherein the grounding member and the first elastic support member are secured to at least one of the first or second conductive covers by one or more fastening elements extending through the first and second through holes.
 4. The electronic device of claim 1: wherein the grounding member is a first resilient grounding member that forms at least a portion of a first ground path from the first conductive surface portion to one of the first or second conductive covers, and wherein each of the mounting assemblies further includes a second resilient grounding member that forms at least a portion of a second ground path from a second conductive surface portion of the plurality of conductive surface portions to the other of the first or second conductive covers.
 5. The electronics device of claim 1: wherein the first and second conductive covers at least partially form a Faraday cage around the electronics board, wherein the grounding member is a first resilient grounding member that forms at least a portion of a first ground path from the first conductive surface portion to at least one of the first or second conductive covers, and wherein each of the mounting assemblies further includes: a second resilient grounding member that forms at least a portion of a second ground path from the first resilient grounding member to at least the other of the first or second conductive covers.
 6. The electronics device of claim 1: wherein the electronics board is between the first elastic support member and the second elastic support member.
 7. The electronics device of claim 6 wherein at least one of the first elastic support member or the second elastic support member includes a plurality of deformable features projecting toward the other of the first elastic support member or the second elastic support member and contacting the electronics board.
 8. The electronics device of claim 6 wherein: the first elastic support member includes a plurality of first deformable features projecting toward the second elastic support member and contacting the second side of the electronics board, wherein the second elastic support member includes a plurality of second deformable features projecting toward the first elastic support member and contacting the first side of the electronics board, and wherein the electronics board is supported between the plurality of first deformable features and the plurality second deformable features.
 9. The electronic device of claim 1: wherein the electronics board includes a through hole, and wherein the second elastic support member includes a bushing portion that extends through the through hole, the bushing portion having a plurality of deformable features extending radially outward therefrom.
 10. The electronic device of claim 1 wherein the electronic device is an ultrasonic imaging device, and wherein the electronics board carries at least one processing device configured to generate visual images based at least in part on ultrasonic signals.
 11. A mounting assembly for mounting a circuit board in an electronic device enclosure having a first conductive cover portion spaced apart from a second conductive cover portion, wherein the first conductive cover portion includes a mounting feature, and wherein the mounting assembly comprises: a first elastomeric isolator configured to be attached to the mounting feature and contact a first side of the circuit board; a second elastomeric isolator configured to be attached to the mounting feature and contact a second side of the circuit board opposite to the first isolator; and a grounding member configured to be attached to the mounting feature adjacent to the second isolator and at least partially form a ground path from the circuit board to the first conductive cover portion.
 12. The mounting assembly of claim 11 wherein the mounting feature is a boss that extends from the first conductive cover portion toward the second conductive cover portion.
 13. The mounting assembly of claim 11 wherein at least one of the first elastomeric isolator or second elastomeric isolator includes a through hole configured to receive a fastening element for attaching the at least one isolator to the mounting feature; and a plurality of projecting surface portions in an annular arrangement around the through hole, wherein the plurality of projecting surface portions are configured to contact the circuit board.
 14. The mounting assembly of claim 11 wherein the grounding member is a unitary member formed from a resilient metallic sheet material.
 15. The mounting assembly of claim 11 wherein the grounding member is a first grounding member and the ground path is a first ground path, and wherein the mounting assembly further comprises a second grounding member configured to be attached to the mounting feature and at least partially form a second ground path from the circuit board to the second conductive cover portion.
 16. The mounting assembly of claim 11 wherein the circuit board includes a conductive surface portion, and wherein the grounding member is a resilient member having a tip portion configured to contact the conductive surface portion and be biased against the conductive surface portion by spring force.
 17. The mounting assembly of claim 16 wherein the conductive surface portion of the circuit board is conductively connected to a ground plane of the circuit board.
 18. The mounting assembly of claim 11: wherein the circuit board includes a conductive surface portion, wherein the grounding member is a resilient member having a generally flat base portion and a distal portion extending from the base portion at an angle, the distal portion including a tip portion, wherein the base portion is configured to receive a fastener for attachment to the mounting feature, and wherein the tip portion is configured to be deflected against the conductive surface portion to maintain contact therewith during movement of the circuit board relative to the electronic device enclosure.
 19. A system for shock mounting a circuit board in an electronic device and reducing electromagnetic interference during operation of the electronic device, wherein the circuit board is substantially enclosed within a first conductive material positioned on a first side of the circuit board and a second conductive material positioned on a second side of the circuit board, opposite to the first side, and wherein the system comprises: means for elastically supporting the circuit board at a plurality of locations between the first and second conductive materials, wherein the means for elastically supporting include a first elastic support member on the first side; and a second elastic support member on the second side of the electronics board opposite to the first side; and at each of the plurality of locations, means for forming a ground path that extends from the circuit board to at least one of the first or second conductive materials.
 20. The system of claim 19 wherein the means for forming a ground path includes a first means for forming a first ground path that extends from the circuit board to the first conductive material, and wherein the system further comprises, at each of the plurality of locations, second means for forming a second ground path that extends from the circuit board to the second conductive material without first passing through the first conductive material. 